Reverse flow cleaning method for medical devices

ABSTRACT

A method for cleaning the lumens of a medical device such as an endoscope by providing a flow and a reverse flow of fluids in interconnected lumens of the medical device.

This application is a divisional of U.S. application Ser. No.09/409,101, filed Sep. 30, 1999, which is now U.S. Pat. No. 6,286,527,which claims the benefit of U.S. Provisional application No. 60/102,663,filed Oct. 1, 1998; U.S. Provisional application No. 60/102,664, filedOct. 1, 1998; and U.S. Provisional application No. 60/117,401 filed Jan.27, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the field of sterilizing andcleaning tubular structures including long, narrow, tubular structures.In particular, it relates to a device and method for cleaning andsterilizing medical devices with lumens.

2. Description of the Related Art

Many tubular structures, in particular flexible fiber endoscopes, definelong tortuous lumens. These lumens are typically from about 1 m to about4 m long with inside diameters from about 0.5 mm to about 6 mm andfrequently contain crevices, bends, connections, restrictions, andirregularities. These instruments are frequently used in diagnosticmedicine, requiring penetration into the human body or other contactwith the human bloodstream. It is, therefore, desirable that they arecleaned, rinsed, sterilized, disinfected, or otherwise treated withfluid chemical disinfectants or sterilants to prevent the crosscontamination and transmission of pathogenic organisms from patient topatient. In order for fluid chemical sterilization to be effective, thechemical must reach all internal and external surfaces. Efficaciousness,therefore, is severely limited by the inherent irregularities present inthe long, narrow, lumens of flexible fiber endoscopes making effectivecleaning and sterilization difficult.

Consistently and quickly cleaning, disinfecting, and sterilizing medicaldevices is an important part of providing quality healthcare. Failure toconsistently clean and sterilize medical instruments leads to unwantedtransmission of bacteria, viruses, and other organisms to and frompatients. Improper handling of medical instruments allows unwantedorganisms access inside the body where they may cause infection anddisease.

Although the terms “sterilization” and “disinfection” are sometimes usedimprecisely, the medical industry and regulatory agencies have moreprecisely defined the following terms including subdividing disinfectioninto high, intermediate, and low level disinfection.

Sterilization is generally defined as the destruction or elimination ofall microbial life forms. Operationally, a sterilizing process is onethat destroys all microbes on a device that has been contaminated with10⁶ bacterial endospores.

High level disinfection is generally defined as the destruction orelimination of all microbial life forms except microbial spores. Highlevel disinfectants however, must show a capability of destroyingbacterial spores over an extended period of time.

Intermediate disinfection is generally defined as the destruction of allmicrobial life forms except bacterial spores and some viruses. However,intermediate disinfection requires the destruction or elimination ofMycobacterium tuberculosis var. bovis, which is a relatively difficultbacterium to destroy.

Low level disinfection is generally defined as the destruction ofvegetative forms of bacteria (such as salmonellae and staphylococci),most fungi, medium sized or lipid containing viruses (such as Herpessimplex virus, hepatitis B virus, and HIV), but not bacterialendospores, mycobacteria, or small or non-lipid viruses (such aspoliovirus and rhinovirus).

The level of disinfection or sterilization desired for a particularpiece of equipment generally depends on the degree of exposure theequipment poses to the patient. For example, sterilization is generallynecessary for equipment that is introduced directly into the human body,either in contact with the blood stream, or in contact with normallysterile areas of the body. High level disinfection is generally requiredfor equipment that contacts mucus membranes, but does not penetratebodily surfaces. Low and intermediate disinfection is generally requiredfor equipment that contacts unbroken skin.

Endoscopes, which are used to probe internal passages of the body, arean exception to the general rule of sterilizing equipment that isintroduced directly into the human body. Ideally, all endoscopes shouldbe cleaned and sterilized between uses. However, due to their delicateoptical equipment, endoscopes remain an exception to the sterilizationrule. The delicate optical equipment and lenses in these devices do notallow conventional methods of sterilization such as autoclaving,ethylene oxide gassing, or soaking for several hours in liquidsterilants. Autoclaving requires high temperatures for sterilization,which damages the optical lenses of the endoscopes. Ethylene oxide gasequipment is expensive and requires several hours to complete thesterilization and degassing process. Repeated soaking in liquidsterilants may also damage some endoscopes. In addition, the high costof these specialized pieces of equipment demands efficient utilizationof the instruments, requiring use of the same endoscope on as manypatients in as little time as feasible. Therefore, soaking in liquidsterilants or sterilization by ethylene oxide gas is not economicallyfeasible because of the long time period required. The demand for rapidreuse results in pressure to shorten or eliminate cleaning,disinfection, and sterilization practices. As a compromise to all ofthese considerations, high level disinfection for endoscopes isconventionally accepted in lieu of sterilization.

Although high level disinfection has been conventionally acceptable, itdoes not provide the level of safety of sterilization. The conventionalrationale for accepting the reduced level of safety is that endoscopescontact mucus membrane and do not provide access to the blood stream.However, endoscopes are routinely used to find lesions in mucus membraneareas that may provide access to the blood stream. In addition, manyendoscopes provide biopsy forceps that are miniature scalpels used tocut biopsy samples from the mucus membrane tissue. These commonpractices provide access to the bloodstream and a potential pathway forunwanted organisms to access all parts of the body. In addition toproviding a direct path to the bloodstream, many endoscopes such asduodenoscopes are used in normally sterile parts of the body.Introducing contaminated equipment into these areas has been shown tocause infection.

The lumens of medical devices have conventionally been difficult toclean, disinfect, and sterilize. Some larger lumens may be cleaned withbrushes. However, lumens that are too small for brushes are generallylimited to cleaning by flushing with fluids such as water or air. Asnoted previously, the lumens also contain crevices, bends, connections,restrictions, and irregularities that restrict flow and hold residualmaterial making cleaning difficult. Before a piece of equipment isdisinfected or sterilized, it is preferably first cleaned. Failure tocompletely clean residual material from the equipment potentially leavesmicroorganisms within and beneath the residual material not easilyaccessible to the disinfectant or sterilant.

Some conventional devices have used special attachments or caps todirect flow into different passages of endoscopes. However, theseattachments create additional attachment points. The unexposed surfacesbetween the attachment and the medical device may not receive completecleaning or sterilization.

Typically, conventional devices and methods of cleaning have useduni-directional flow to clean long narrow devices with lumens. It isbelieved that irregularities and restrictions in the passages create airpockets or sheltered areas along the passages. For example, as the fluidflows around corners, the fluid tends to flow to the outside of thecorner, leaving an air pocket or undisturbed liquid or material on theinside edge. Fluid flow is also reduced on the downstream side of anyrestriction.

Some devices, such as those disclosed in Ishii 4,526,623, use suctionfrom a syringe to draw residual fluid in the lumens or to draw fluidfrom an additional fluid container. However, the use of suction maycollapse lumens, introduce additional air pockets in the lumen, andcreate the need for additional attachments. Suction may also require theuse of check valves to properly control the removal of fluid and reducethe amount of air introduced into the medical device. Check valves mayalso reduce or eliminate complete removal of the fluid. Cleaning bysuction only removes liquid from multiple lumens until one lumencontains air. Once a single lumen contains air, only air is drawnthrough the device because air flows more easily than liquid. Therelative differences in the size of the lumens would also cause certainlumens to drain more quickly, leaving liquid in the remaining lumens.Lastly, the syringe method and device of Ishii is not easily automated.

Sterilization methods have also included immersion or soaking of medicaldevices in liquid sterilant. Sterilization by soaking typically requiresseveral hours and air bubbles may become trapped inside the lumens,causing inconsistent results.

A new and useful device and method is needed that overcomes the problemsassociated with conventional methods of cleaning and sterilizing tubularstructures, including long, narrow, tubular structures, particularlymedical devices with lumens, by providing a device and method thatprovides a reverse flow through the tubular structures.

SUMMARY OF THE INVENTION

It is an object of the reverse flow cleaning and sterilizing device andmethod in accordance with the present invention to solve the problemsoutlined above that have heretofore inhibited the successful cleaningand sterilization of tubular structures, in particular, long, narrow,tubular structures.

More particularly, the apparatus and method of the reverse flow cleaningand sterilizing device in accordance with the present invention providesfor the cleaning and sterilization of medical devices with lumens,particularly endoscope lumens.

The unique sterilization and cleaning device in accordance with thepresent invention broadly includes a first valve and a second valve. Thefirst and second valves are each in fluid communication with a fluidsupply at a positive pressure. The first valve is in fluid communicationwith a first tubular structure having a proximal end and a distal endwith the first valve in fluid communication with the proximal end. Thesecond valve is in fluid communication with a second tubular structurehaving a proximal and a distal end with the second valve in fluidcommunication with the proximal end. The first tubular structure is influid communication with the second tubular structure. The first andsecond valves selectively switch between a first position and a secondposition. The first position causes a first fluid flow path and thesecond position causes a second fluid flow path. At least part of thesecond fluid flow path is opposite the first fluid flow path. In thefirst position the first valve is open to the fluid supply and thesecond valve is closed to the fluid supply. In the second position thesecond valve is open to the fluid supply and the first valve is closedto the fluid supply.

The device may also provide that either both fluid flow paths start atone end of a medical device or one fluid flow path may start in acontrol head or center of the medical device.

The device may also provide that the distal end of at least one of thetubular structures is open to a drain at about atmospheric pressure.

The device may also provide that in the first position the second valveis open to a drain line and in the second position the first valve isopen to a drain line.

The device may also provide that the fluid supply has a flow volume fromabout 100 ml/min to about 1400 ml/min and a flow velocity from about 50cm/sec to about 500 cm/sec and a pressure below about 20 psi for about 1minute to about 20 minutes.

The device may also provide a third and a fourth valve, a third and afourth tubular structure, and a third and a fourth position.

The device may also be used in an automatic reprocessing device so thata central processor controls positioning of the valves.

The apparatus and method in accordance with the present inventionprovides both a method of sterilization of tubular structures and amethod of cleaning the lumens of a medical device.

The sterilization method broadly includes the sterilization of theinterior of a tubular structure comprising: a) providing a tubularstructure, b) providing a sterilizing fluid c) causing the sterilizingfluid to flow at a positive pressure through the tubular structure in afirst fluid flow path, and d) causing the sterilizing fluid to reverseflow at a positive pressure through the tubular structure in a secondfluid flow path, so that at least part of the second fluid flow path isopposite the first fluid flow path.

The sterilization method may also include providing the sterilizingfluid at a temperature from about 20 degrees C. to about 50 degrees C.and from about 1 minute to about 20 minutes.

The sterilization method may also include providing a tubular structurehaving a diameter equal to or less than about 6 mm and the flowing andthe reverse flowing have a flow velocity from about 50 cm/second toabout 500 cm/second, a flow volume from about 100 ml/min to about 1400ml/min, and a pressure below about 20 psi.

The sterilization method may also include starting the first fluid flowpath and starting the second fluid flow path in one end of a medicaldevice.

The device may also provide that one fluid flow path may start in acontrol head or other attachment point of the medical device.

The sterilization method may also include providing the device of thepresent invention.

The sterilization method may also include controlling the flowing andthe reverse flowing by a central processor.

The present invention may also include a method of cleaning a medicaldevice with lumens. The cleaning method broadly includes a method ofcleaning the lumens of a medical device including a) providing a medicaldevice with a first lumen and a second lumen, each lumen having aproximal end and a distal end, the first lumen in fluid communicationwith the second lumen, and the second end of at least one of the lumensopen to a drain at about atmospheric pressure; b) providing a cleaningfluid; c) causing the cleaning fluid to flow at a positive pressurethrough the lumens in a first fluid flow path starting at the proximalend of the first lumen; and d) causing the cleaning fluid to reverseflow at a positive pressure through the lumens in a second fluid flowpath starting at the proximal end of the second lumen, such that atleast part of the second fluid flow path is opposite the first fluidflow path.

The cleaning method may also include providing a medical device with thefirst end of each lumen located in the same end of the medical device.

The cleaning method may also provide that either both fluid flow pathsstart at one end of a medical device or one fluid flow path may start ina control head or other attachment point of the medical device.

The cleaning method may also include draining the first fluid flow paththrough the proximal end of the second lumen and draining the secondfluid flow path through the proximal end of the first lumen.

The cleaning method may also include providing the flowing and thereverse flowing at a flow velocity of from about 50 cm/sec to about 500cm/sec, a flow volume from about 100 ml/min to about 1400 ml/min, and apressure below about 20 psi.

The cleaning method may also include providing the device of the presentinvention.

The cleaning method may also provide controlling the flowing and thereverse flowing by a central processor.

One advantage of the present invention is improved sterilization. Thepresent invention provides better application of the fluid to all partsof the interior of tubular structures. Improved application of the fluidto the interior of the tubular structure results in faster and moreconsistent sterilization.

Another advantage is that air pockets are consistently removed. Thepresent invention improves sterilization and cleaning by providingbetter application of fluid by consistently removing air pockets fromthe interior of the tubular structures. Flowing and reverse flowing at apositive pressure provides consistent removal of air pockets. Soaking orholding fluid in the tubular structures does not consistently remove airpockets resulting in inconsistent cleaning and sterilization.

Another advantage is that the fluid obtains improved access to cracks,crevices, and restrictions. Flowing and reverse flowing at a positivepressure forces fluid into cracks, crevices, and restrictions from morethan one direction. Flowing from one direction or flowing at a negativepressure does not force fluid into the cracks and crevices, especiallydownstream of a restriction, causing inconsistent sterilization andcleaning.

Another advantage is that residual liquids and materials remaining inthe lumens are more adequately displaced with fluid. Liquid, such asleft over rinse water may not be completely displaced using anunidirectional flow pattern. As a result, the chemicals (activeingredients) in the fluid must diffuse into the rinse water beforesterilization may occur. The present invention provides betterdisplacement of residual materials and liquids providing faster and moreconsistent sterilization and cleaning.

Another advantage is that soaking is not required. The present inventionis not limited by the use of large volumes of sterilizing fluid neededto immerse the entire tubular structure, saving sterilization fluid.

Another advantage is that sterilization can be accomplished morequickly. Long soaking times of hours required for immersionsterilization may be reduced to about minutes for the present invention.Quicker sterilization results in better utilization of medicalequipment.

Another advantage is that sterilization can be accomplished moreconsistently. Flowing sterilizing fluid from more than one direction andforcing the sterilizing fluid into cracks and crevices with positivepressure reaches the interior surfaces of tubular structures moreconsistently. More consistent application of the sterilizing fluid tothe interior surfaces provides more consistent sterilization.

Another advantage is that the present invention can be attached to thesupply ports of the endoscope. The present invention may be attached toone end of a medical device such as an endoscope without any attachmentsto the distal end or insertion section of the medical device. Othermethods using suction pressure require the attachment of a fluid sourcein addition to the suction source requiring additional attachments. Adevice that connects to one end of the medical device provides an easierand more centralized attachment and eliminates the need for additionalattachments.

Another advantage is that the present invention provides an alternativemethod of attachment to the air/water channel, particularly if thedevice does not have a gas or CO₂ channel. The present invention mayprovide for attachment to the air/water channel at the air/water controlcylinder.

Another advantage is that the present invention reduces the number ofattachments that cause additional contamination points. Each additionalattachment creates an area between the attachment and the medical devicethat is difficult to reach with fluid. The more attachments the greaterthe inconsistency of cleaning and sterilization.

Another advantage is that the present invention uses positive pressureflow. In addition to the improved penetration capabilities previouslydescribed, positive pressure flow is easier to provide. Positivepressure provides a greater range of pressures and can be more easilyprovided through a greater variety of positive pressure pumps. Positivepressure flow provides both the pressure source and the fluid source atone location, simplifying connections and automation. Positive pressureis also safer because contaminates cannot be drawn into the devicethrough leaks in the system.

Another advantage of the present invention is that it may be operated attemperatures less than 50 degrees C. Operating at temperatures below 50degrees C. prolongs the life of medical devices and reduces burnhazards.

Another advantage is that the present invention may be easily automated.The use of valves controlled by a central processor may be easilyautomated, particularly in an automatic reprocessing device. Theelimination of manually operated equipment and methods such as syringesprovides for automation.

These and other objects and advantages of the present invention willbecome apparent during the course of the following detailed descriptionand appended claims. The invention may best be understood with referenceto the accompanying drawings, wherein an illustrative embodiment isshown.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of the device in a first flow position.

FIG. 2 is a schematic drawing of the device in a second flow position.

FIG. 3 is a side cross sectional view of an endoscope connected to thedevice showing a first and a third fluid flow path.

FIG. 4 is a side cross sectional view of an endoscope connected to thedevice showing a second and fourth fluid flow path.

FIG. 5 is a schematic drawing of the device in an alternate second flowposition.

FIG. 6 is a schematic drawing of the device in an alternate first flowposition.

FIG. 7 is a side cross sectional view of an endoscope connected to thedevice showing an alternate first fluid flow path.

FIG. 8 is a side cross sectional view of an endoscope connected to thedevice showing an alternate second fluid flow path.

FIG. 9 is a schematic drawing of the device incorporated into anautomatic endoscope reprocessing machine controlled by a centralprocessor.

FIG. 10 is a schematic drawing of the device incorporated into analternate embodiment of an automatic endoscope reprocessing machinecontrolled by a central processor.

FIG. 11 shows an exterior perspective view of a medical instrumentreprocessing device having one of a pair of chemical supply draweraccess doors in an open position and one of a pair of reprocessing baycabinet access doors in an open position.

FIG. 12 shows a perspective view of the major components of a medicalinstrument reprocessing device in one possible arrangement relative toeach other and positioned in a representation of thecompartmentalization provided by an exterior housing. Two reprocessingbays are represented in the reprocessing bay cabinet of the housing; oneconfigured with a reprocessing bay door in the open position and theother, presented in broken lines, configured without the necessaryreprocessing bay door.

FIG. 13 shows a perspective view of two reprocessing bays, withoutaccess panels, of a medical instrument reprocessing device. Onereprocessing bay is shown in a partial sectional view disclosing anexterior pressure washing assembly.

FIG. 14 shows a perspective sectional view of a heater assembly of amedical instrument reprocessing device invention.

FIG. 15 shows a front elevational view of the movable cassette assemblyof a medical instrument reprocessing device.

FIG. 16 shows a schematic representation of the hydraulic system andpneumatic system of a medical instrument reprocessing device.

DETAILED DESCRIPTION OF THE INVENTION GENERAL ASSEMBLY

Referring to FIGS. 1, 2, 5, 6, 9, and 10, the device 10 in accordancewith the present invention broadly includes a first valve 80 and asecond valve 82. However, additional valves for additional tubularstructures may be provided. The first and second valves 80,82 are eachin fluid communication with to a fluid supply 84 at a positive pressure.The first valve 80 is in fluid communication with a first tubularstructure 94, the first tubular structure 94 having a proximal end 98and a distal end 100, the first valve 80 is in fluid communication withthe proximal end 98. The tubular structures typically have a length thatis about 200 to about 8,000 times the inside diameter. The second valve82 is in fluid communication with a second tubular structure 96, thesecond tubular structure 96 having a proximal end 102 and a distal end104, the second valve 82 is in fluid communication with the proximal end102. The first tubular structure 94 is in fluid communication with thesecond tubular structure 96. The first and second valves 80, 82selectively switch between a first position 106 and a second position108. In the first position 106, the first valve 80 is open to the fluidsupply 84 and the second valve 82 is closed to the fluid supply 84. Inthe second position 108 the second valve 82 is open to the fluid supply84 and the first valve 80 is closed to the fluid supply 84. The firstposition 106 causes a first fluid flow path 110 and the second position108 causes a second fluid flow path 112. At least a part of the secondfluid flow path 112 is opposite the first fluid flow path 110.

The device 10 may also provide that the distal end 100, 104 of at leastone of the tubular structures 94, 96 is open to a drain 114 at aboutatmospheric pressure.

The device 10 may also provide that in the first position 106 the secondvalve 82 is open to the drain line 88 and in the second position 108 thefirst valve 80 is open to the drain line 88.

The device 10 may also provide that the fluid supply 84 has a flowvolume from preferably about 100 ml/min to about 1400 ml/min. Preferablythe flow volume is about 100 ml/min to about 250 ml/min for tubularstructures of about 1 mm to about 2 mm in diameter and about 600 ml/minto about 1400 ml/min for tubular structures of about 3 mm to about 6 mmin diameter. The fluid supply 84 has a flow velocity from preferablyabout 50 cm/sec to about 500 cm/sec and most preferably about 50 cm/secto about 250 cm/sec. The fluid supply 84 has a pressure preferably belowabout 20 psi and most preferably from about 10 psi to about 20 psi.Pressures above about 20 psi may damage the endoscope and are notrecommended by manufacturers. The sterilizing fluid 116 is preferablyprovided for about 1 minute to about 20 minutes and most preferablyabout 10 minutes.

The device 10 may also provide a third and a fourth valve, a third and afourth tubular structure, and a third and a fourth position.

The device 10 may also be used in an automatic reprocessing device sothat a central processor controls positioning of the valves.

The device 10 may be used to process a medical device with lumens suchas an endoscope 12 described below. Endoscopes may be about 1 m to about4 m long and have lumens ranging from about 0.5 mm to about 6 mm.

As shown in FIGS. 3,4 7, and 8, endoscope 12 may have a plurality oftubular structures or lumens 14. The lumens 14 typically consist of awater channel 16, a suction channel 18, an air channel 20, and a CO₂channel 22. The endoscope 12 typically has an insertion section 24extending from a control section 26 and an umbilical section 28 alsoextending from the control section 26. The lumens 14 are defined insidethe endoscope 12 and extend through the endoscope 12 from the insertionsection 24 and are in fluid communication with control valve cylinders30 and extend and are in fluid communication with the lumens 14 in theumbilical section 28. There are typically three control valve cylinders30 including an air/water cylinder 32, a suction cylinder 34, and a CO₂cylinder 36.

UMBILICAL SECTION

During use, the light guide or umbilical section 28 of the endoscope 12connects the lumens 14 of the endoscope 12 to a supply of air, water,and CO₂ via supply ports located at the distal end 52 of the umbilicalsection 28. The lumens 14 include an air channel 20, a suction channel18, a water channel 16 and a CO₂ channel 22. The umbilical section has asuction supply port 38 in fluid communication with the suction channel18, a CO₂ supply port 40 in fluid communication with the CO₂ channel 22,an air supply port 44 in fluid communication with the air channel 20,and an air/water supply port 42 in fluid communication with the waterchannel 16 and the air channel 20. The lumens 14 extend through theumbilical section 28 and are in fluid communication with the controlcylinders 30 located in the control section 26.

CONTROL SECTION

The control section 26 is located in the middle of the endoscope 12 andcontains the control cylinders 30 and the lens 132 for viewing thoughthe endoscope 12. During normal operation, the control cylinders 30contain control valves and provide operational control of the flow ofair, water, and CO₂. During processing, cleaning, and sterilization, thecontrol valves are removed from the air/water control cylinder 32 andthe suction cylinder 34 and the openings are capped. The CO₂ controlvalve in the CO₂ cylinder 36 is left in the open position. The CO₂cylinder 36 is in fluid communication with both the CO₂ channel 22 fromumbilical section 28 and the CO₂ channel 22 that is in fluidcommunication with the air channel 20 between the air/water cylinder 32and the insertion section 24. The air/water cylinder 32 is in fluidcommunication with four channels, a) the air channel 20 from theumbilical section 28, b) the water channel 16 from the umbilical section28, c) the air channel 20 from the insertion section 24, and d) thewater channel 16 from the insertion section 24. The insertion section 24typically has three instead of four lumens because the CO₂ channel 22joins and is in fluid communication with the air channel 20 in thecontrol section 26 downstream of the control cylinders 30.

INSERTION SECTION

The insertion section 24 is connected to the control section 26 of theendoscope 12 and is the portion of the endoscope 12 that is insertedinto the patient during use. The insertion section 24 has an air/waternozzle 46 and a suction opening 48 located at the distal end 54 of theinsertion section 24. The water channel 16 and air channel 20 merge inthe insertion section 24 to form an air/water channel 56. The air/waterchannel 56 is in fluid communication with the air channel 20 and thewater channel 16 and with the air/water nozzle 46. The air channel 20 isin fluid communication with the air/water cylinder 32 and with theair/water channel 56. The water channel 16 is in fluid communicationwith the air/water cylinder 32 and with the air/water channel 56. Thesuction channel 18 is in fluid communication with the suction cylinder34 and with the suction opening 48. The endoscope may also have aforceps or biopsy port 50 located in the control section 26. The biopsyport 50 is in fluid communication with the suction channel 18 betweenthe suction cylinder 34 and the suction opening 48.

SUCTION CHANNEL

The suction channel 18 is typically from about 3 mm to about 6 mm indiameter. The suction channel 18 can be subdivided into an umbilicalsuction channel 18 a, a control suction channel 18 b and an insertionsuction channel 18 c. The umbilical suction channel 18 a is the portionof the suction channel 18 from the suction supply port 38 to the suctioncylinder 34.

The control suction channel 18 b is the portion from the suctioncylinder 34 to the biopsy port 50. The insertion suction channel 18 c isthe portion from the biopsy port 50 to the suction opening 48.

AIR CHANNEL

The air channel 20 is typically from about 1 mm to about 2 mm indiameter. The air channel 20 can be subdivided into an umbilical airchannel 20 a, a control air channel 20 b, and an insertion air channel20 c. The umbilical air channel 20 a is the portion from the air/watersupply port 42 and the air supply port 44 to the air/water cylinder 32.The control air channel 20 b is the portion from the air/water cylinder32 to the CO₂ channel 22. The insertion air channel 20 c is the portionfrom the CO₂ channel 22 to the air/water channel 56.

WATER CHANNEL

The water channel 16 is typically from about 1 mm to about 2 mm indiameter. The water channel 16 can be subdivided into an umbilical waterchannel 16 a and an insertion water channel 16 c. The umbilical waterchannel 16 a is the portion from the air/water supply port 42 to theair/water cylinder 32. The insertion water channel 16 c is the portionfrom the air/water cylinder 32 to the air/water channel 56.

CO₂ CHANNEL

The CO₂ channel 22 is typically from about 0.5 to about 2 mm indiameter. The CO₂ channel 22 is particularly complex and restricted inthe CO₂ valve. The CO₂ or gas valve utilizes narrow passages andrestrictions. The CO₂ channel 22 may be subdivided into an umbilical CO₂channel 22 a, and a control CO₂ channel 22 b. The umbilical CO₂ channel22 a is the portion from the CO₂ supply port 40 to the CO₂ cylinder 36and the control CO₂ channel 22 b is the portion from the CO₂ cylinder 36to the air channel 20.

THE DEVICE

As previously described and as shown in FIGS. 1 through 10, the device10 broadly includes a first valve 80 and a second valve 82. The firstand second valves 80, 82 are each in fluid communication with a fluidsupply 84.

In the preferred connection to an endoscope, the first valve 80 is influid communication with the CO₂ supply port 40 and the second valve 82is in fluid communication with the air/water supply port 42. Theconnection to the air/water supply port 42 may also preferably include aconnection to the air supply port 44 using a T-connection. In addition,either valve 80, 82 may be connected to either the CO₂ supply port 40 orthe air/water supply port 42.

In an alternative connection to an endoscope, the first valve 80 is influid communication with the air/water supply port 42 and the secondvalve 82 is in fluid communication with the air/water cylinder 32. Theconnection to the air/water supply port 42 may also include a connectionto the air supply port 44 using a T-connection. In addition, eithervalve 80, 82 may be connected to either the air/water cylinder 32 or theair/water supply port 42.

The valves 80, 82 are preferably three-way valves that provide threeconnections to the valve and allow flow between any two connections.However, the valves may be two-way valves or a combination of two-wayvalves. Preferably one connection is in fluid communication with thefluid supply 84, a second connection is connected to a first tubularstructure 94, and one connection is connected to a second tubularstructure 96. The valves 80, 82 are preferably Predyne B3314 three wayvalves with ⅛ inch NPT threads and a fluid constant (Cv) of 0.11. Thevalves 80, 82 may be in fluid communication with the tubular structures94, 96 by any means known in the art such as tubing and flexiblecouplings.

The connecting lines 134, including the fluid supply 84 and the drainline 88 may be of any material used in sterilizing and cleaningprocessing equipment. The connecting lines are preferably about ¼ inchto about ½ inch diameter plastic tubing, preferably polyethylene.

The device 10 may also include a blocking valve 118 in the fluid supply84 to direct the flow of fluid to a limited number of tubularstructures. Limiting the flow to one or two lumens allows the use of asmaller fluid supply pump. Limiting the flow to one lumen at a time alsoassures that each lumen receives adequate flow and is not affected bydifferent lumen sizes or by blockages. The blocking valve 118 may alsobe used in testing procedures to determine if blockages exist in thelines or lumens.

The fluid may consist of a cleaning fluid 86, a sterilizing fluid 116,or any other fluid that is desired to reach all portions of the tubularstructure 94,96. The fluid may be a liquid or a gas. The sterilizingfluid 116 may comprise a liquid performic acid based sterilant, asdescribed in provisional application Ser. No. 60/102,664 entitledMULTI-PART ANTI-MICROBIAL CONCENTRATE SYSTEM ACTIVATED FLUID,USE-DILUTION FLUID, METHOD OF MAKING SAME, AND METHOD OF STERILIZINGWITH THE USE-DILUTION FLUID, filed on Oct. 1, 1998, the disclosure ofwhich is hereby incorporated by reference.

The device and method of the present invention may be incorporated intoan endoscope reprocessing device, as described in provisionalapplication Ser. No. 60/102,663 entitled ENDOSCOPE REPROCESSING ANDSTERILIZATION SYSTEM, filed on Oct. 1, 1998, the disclosure of which ishereby incorporated by reference. FIGS. 11-16 and the followingdescription of the medical reprocessing device are from the abovedescribed provisional application.

AUTOMATIC MEDICAL INSTRUMENT REPROCESSING DEVICE

Referring now to FIGS. 11-15, an endoscope reprocessing andsterilization system is shown and generally indicated as 810. Anexterior housing 812 is provided to arrange, contain and provideprotection for the components of the reprocessing system 810. Areprocessing bay cabinet 814 of the housing 812 is configured to containat least one reprocessing bay 816. The reprocessing bay cabinet 814 isequipped with at least one cabinet access door 818. The embodiment shownin FIG. 11 is configured to have two cabinet access doors 818 a, 818 bwhich are shown with one cabinet access door 818 a in the open positionallowing access to the at least one reprocessing bay 816 and the othercabinet access door 818 b in the closed position. The preferredembodiment shown in FIGS. 11-12 is configured to have two independentlyoperated reprocessing bays 816 a, 816 b, although it is not limited totwo independently operated reprocessing bays 816.

A chemical supply drawer 820, which is configured to contain supportcomponents, generally indicated at 822, is equipped with at least onedrawer access door 824.

The embodiment shown in FIG. 11 is configured to have two chemicalsupply drawer access doors 824 a, 824 b which are shown with one draweraccess door 824 a in the open position allowing access to the supportcomponents 822 and the other drawer 820 access door 824 b in the closedposition. The support components 822, contained within the chemicalsupply drawer 820, can include a soap container 826, a plurality ofchemical sterilant component containers 828, 830, a water heater 832, ahot water tank 834, a reaction chamber 836, a load sensor 838, anelectric motor and pump 840, an air compressor 842, and a compressed airtank 844. The preferred embodiment shown in FIG. 12 is configured withtwo chemical sterilant component containers 828, 830 which serve tocontain the two components of a multi-component concentrate system. Thereprocessing system 810 may include a greater or lesser number ofchemical sterilant component containers depending upon the number ofcomponents required for the sterilant used. In the preferred embodiment,each of the two reprocessing bays 816 a, 816 b is independentlyoperated. To support such independent operation, the device 810, asshown in FIG. 12, is equipped with an independently operated electricmotor and pump 840 a, 840 b, one for each reprocessing bay 816 a, 816 b.

Hydraulic and pneumatic connections between each of the componentscontained within the chemical supply drawer 820 and the reprocessingbays 816 a, 816 b contained within the reprocessing bay cabinet 814 areshown only in FIG. 16 to simplify presentation of the major componentsshown in FIGS. 11-15.

The reprocessing bays 816 a, 816 b are identically configured andindependently operated. Detail discussion of the reprocessing baycomponents and operations will, for demonstration purposes, be limitedto descriptions of reprocessing bay 816 a.

The reprocessing bay 816 a is equipped with a reprocessing bay door 846,which serves to seal the reprocessing bay during operation. Thereprocessing bay door 846 can be constructed so as to provide thermaland sound proofing features. The vertical side walls 848 a, 848 b, backwall 850, ceiling member 852, and floor member 854 can also be formed toprovide thermal and sound proofing features. The thermal and soundproofmg features can be provided by manufacturing the side walls 848 a,848 b, back wall 850, ceiling 852, floor 854, and door 846 structures ofmaterials such as, for example, plastics, steel, glass, and the like.

The reprocessing bay 816 a is equipped with at least one and preferablytwo identical rotating arm members 856. In the preferred embodiment, thetwo rotating arm members 856 a, 856 b are separately rotatably mountedon a central portion of opposing side walls 848 a, 848 b. The followingdetailed description applies to all rotating arm members 856 butreference is limited to rotating arm member 856 a, which is best shownin FIG. 13. The rotating arm member 856 a includes a central hub sleeve858 rotatably connected around a rotating arm hub member 860 whichextends outwardly at about a right angle from the central portion ofside wall 848 a. At least two counterbalanced spray arms 862 a and 862 bare connected on approximate opposing sides of the central hub sleeve858. Each spray arm 862 a, 862 b defines a spray arm lumen 864 a, 864 b(shown in part with broken lines). The spray arm lumen 864 a, 864 bextends at least a portion of the length of the spray arm 862 a, 862 band serves to operatively connect a hub sleeve lumen 866 defined withinthe central hub sleeve 858 with a plurality of spray jets 868 defined inthe wall of the spray arms 862 a, 862 b. Together the interconnected hubsleeve lumen 866, spray arm lumens 864 a, 864 b and spray jets 868provide a conduit for the pressurized flow of washing, rinsing andsterilizing fluids from a rotating fluid connector 870, defined withinthe hub member 860, to the interior of the reprocessing bay 816 a. Thewashing, rinsing and sterilizing fluids are provided to the rotatingfluid connector 870 by tubular conduits as shown in FIG. 16. Optionally,one or more of the side walls 848 a, 848 b, back wall 850, ceiling 852,floor 854 and door 846 members walls of the reprocessing bay can beprovided with wall spray jets 869 which are fluidly connected to therotating fluid connector 870 or, alternatively, to a separate fluidinlet connector. Tubular conduits used in the present invention can beformed of metal, plastic, glass and the like as is well known in theart.

At the each distal end 872 a, 872 b of spray arms 862 a, 862 b is aspray nozzle 874 a, 874 b, which is configured with a plurality of sprayopenings 876. The spray openings 876 are operatively connected to thespray arm lumens 864 a, 864 b and together with the spray-jets 868direct sterilant and rinse fluids into the central portion of thereprocessing bay 816 a. Spray nozzles 874 a, 874 b may also rotate aboutthe longitudinal axis of spray arms 862 a, 862 b. In addition to thefluid directing function for sterilizing and rinsing, the spray openings876 and spray jets 868 direct the pressurized flow of fluid out of thespray nozzle 874 a, 874 b and spray arms 862 a, 862 b in such a manneras to effect aggregate impulse which produces a reactive rotationalforce of the spray arms 862 a, 862 b around the central hub 860.

The reprocessing bay 816 a can have at least one cassette guide 878which serves to guide a cassette 880 from a loading position outside ofthe reprocessing bay 816 a to an operational position inside thereprocessing bay 816 a. Preferably the reprocessing bay 816 a isequipped with two cassette guides, an upper cassette guide 878 a and alower cassette guide 878 b. The upper cassette guide 878 a can besecured to the ceiling 852 or alternatively to the upper portion of theback wall 850 of reprocessing bay 816 a. The lower cassette guide 878 bcan be secured to the floor 852 or alternatively the lower portion ofthe back wall 850 of reprocessing bay 816 a. The interior surface of thedoor 846 of reprocessing bay 816 a can be configured to have a doorguide 882 which aligns with the lower cassette guide 878 b to facilitatethe positioning of the cassette 880 into or out of the reprocessing bay816 a.

The cassette 880 is configured to removably secure a medical device suchas an endoscope within the reprocessing bay 816 a. The medical device ispreferably suspended above the washing, rinsing or sterilizing fluid.The cassette 880 can be equipped with a plurality of clamping members882 for holding the medical device being sterilized in position in thereprocessing bay 816 a. The cassette can be removably positioned in thereprocessing bay 816 a in a suspended orientation to the upper cassetteguide 878 a. As best shown in FIGS. 12 and 15, the cassette ispreferably removably positioned between the upper cassette guide 878 aand the lower cassette guide 878 b. As best shown in FIG. 15, thecassette 880 can be configured to have an upper rotational member 886and a lower rotational member 888 which are independently able to freelyrotate about an axle member 890 a, 890 b which is fixedly secured to theupper and lower portions of the cassette 880. The upper rotationalmember 886 and the lower rotational member 888 are each provided with aguiding groove 892, 894, respectively. The guiding grooves 892, 894 aresized and configured to complement the size and shape of the uppercassette guide 878 a and the lower cassette guide 878 b, respectively,for purpose of facilitating ease of movement of the cassette into andout of the reprocessing bay 816 a.

In addition, the guiding groove 894 is sized and configured tocomplement the door guide 882 size and shape so as to guide andfacilitate movement of the lower rotational member 888 across the innersurface of the reprocessing bay door 846 when the bay door 846 is in theopen position.

Extending into the upper portion of the reprocessing bay 816 a is amedical device connector 896 which is configured to provide a fluidtight fitting for a wide variety of medical devices, such as endoscopes.It is within the concept of the present invention to provide connectionadapters that will permit a fluid tight fitting during pressuresterilization of the lumen of a wide variety of medical devices.Washing, rinsing and sterilizing fluids are provided to the medicaldevice connector through tubing conduits as shown in FIG. 16.

The floor member 854 of the reprocessing bay 816 a is configured toserve as a reservoir 898 for collection of fluids which have beensprayed onto or through the medical device being reprocessed andsterilized in the reprocessing system 810. The reservoir can be equippedwith a filtration system 900 of at least two levels of filtration. Asump drain 902 for collection of fluids is provided in the lower portionof the reservoir 898. The size of the reservoir 898 and the verticalpositioning of the reprocessing bays 816 allows the reprocessing system810 to operate and recirculate about 2-5 liters of sterilant. Thereprocessing system 810 preferably operates with about 3 liters ofsterilant.

In operation, the preferred embodiment of the present invention providesfor asynchronous reprocessing of two endoscopes with overlapping cycletime periods. Chemical components for the sterilant are heated andmeasured as they are moved to and mixed in the reaction chamber 836. Thesterilant temperature is monitored and controlled and the reaction ofthe chemical components in the reaction chamber 836 is timed under thecontrol of a central processor 912. The sterilant's refractive index ismeasured to ensure the chemical reaction is complete and to verify thepresence of the sterilant. Water is added to dilute the sterilant to theuse-dilution concentration. Two endoscopes can be reprocessed andsterilized independently and asynchronously using reprocessing bays 816a, 816 b. The endoscopes are mounted on the cassettes 880 and connectedto the medical device connector 896 through which the lumen of theendoscope will be pressure washed and sterilized. The reprocessing baydoors 846 are secured and the endoscopes are internally and externallywashed with soap and water and rinsed. Just prior to the sterilizationcycle, the endoscopes are rinsed with hot water to ensure the sterilantwill not be cooled upon contact with the endoscopes. The endoscopes arethen sterilized internally and externally with sterilant prepared in thereaction chamber 836 just prior to use. The cleaning and sterilizationof the endoscope lumen through the medical device connector 896 isassisted by a flow of liquid (soap and water, rinse water, and sterilantin turn) which receives a superimposed pulsating flow of air. Thispulsating flow of air causes the liquid flow to become severely unsteadyresulting in a scrubbing action on the lumen wall of the endoscope.

Operation of the reprocessing system 810 is monitored by sensors,including those described above, which provide information to thecentral processor 912. The central processor 912 receives cycle programinstructions from a user through the user interface 952. The userinterface can be equipped with any form of command signal keys orbuttons as is well known in the art. Visual displays of user commandswhich are entered as well as central processor 912 responses, errormessages, status notifications and the like can be presented for theuser at the user interface 952. A printer capability can be included topermit the central processor 912 to provide written records of anyaspect of reprocessing system operation to the user. Printed records ofspecific endoscope sterilization can also be printed at the completionof a reprocessing and sterilization cycle. All aspects of the operationof the reprocessing system 810 can be controlled by the centralprocessor 912, to include measuring and mixing of chemical componentsfor the sterilant, metering of water to the reaction chamber 836 forsterilant dilution purposes, washing, rinsing and sterilizing cycles,self-sterilizing, blockage detection and user notification, door ajarsensing and responsive operation termination, and other similar systemmonitoring and operational controls.

IN OPERATION

In operation, the valves 80, 82 alternate between a first position and asecond position as described above causing a first fluid flow path 110and a second fluid flow path 112. In describing the fluid flow paths110, 112, downstream is in the flow direction away from the distal end52 of the umbilical section 28 and towards the distal end 54 of theinsertion section 24.

Referring to FIGS. 3, 4, 7, and 8, in the preferred connection to anendoscope, when the device 10 is in the first position 106 causing afirst fluid flow path 110, the first valve 80 is open to the fluidsupply 84 allowing fluid to flow downstream through the CO₂ supply port40, downstream through the umbilical CO₂ channel 22 a, downstreamthrough the CO₂ cylinder 36, downstream through the control CO₂ channel22 b, into the air channel 20, splitting into two flows, the first flowis upstream (first upstream flow) into the control air channel 20 b, andthe second flow is downstream into the insertion air channel 20 c,downstream into the air/water channel 56, through the air/water nozzle46 and exits the endoscope 12 to a drain 114 at about atmosphericpressure. The first upstream flow continues into the control air channel20 b and flows upstream into the air/water cylinder 32. From theair/water cylinder 32, the fluid splits and flows three ways; a)upstream through the umbilical water channel 16 a and out the air/watersupply port 42 through the second valve 82 to the drain line 88, b)upstream through the umbilical air channel 20 a and out the air/watersupply port 42 and air supply port 44 through the second valve 82 and tothe drain line 88, and c) downstream through the insertion water channel16 c, downstream through the air/water channel 56, through the air/waternozzle 46 and exits the endoscope 12 to a drain 114 at about atmosphericpressure. The downstream flow through the insertion water channel 16 cmay flow upstream depending on the relative pressure loss between thevarious channels.

In a preferred connection to an endoscope, when the device is in thesecond position 108 causing a second fluid flow path 112, the secondvalve 82 is open to the fluid supply 84 allowing fluid to flowdownstream through the air/water supply port 42 and air supply port 44and downstream into both the umbilical water channel 16 a and theumbilical air channel 20 a meeting at the air/water cylinder 32. Thefluid splits and flows downstream through control air channel 20 b anddownstream through the insertion water channel 16 c, the flow continuesthrough the insertion water channel 16 c and downstream through theair/water channel 56 and through the air/water nozzle 46 and exits theendoscope 12 to a drain 114 at about atmospheric pressure. The flowcontinues downstream through the control air channel 20 b and splits andflows upstream into the CO₂ control channel 22 b and downstream throughthe insertion air channel 20 c. The flow continues downstream throughthe insertion air channel 20 c through the air/water channel 56 andexits the endoscope 12 to a drain 114 at about atmospheric pressure. Theflow continues upstream through the control CO₂ channel 22 b, upstreamthrough the CO₂ cylinder 36, upstream through the umbilical CO₂ channel22 a, upstream through the CO₂ supply port 40, and through the firstvalve 80. The fluid flows through the first valve 80 and to the drainline 88.

The second valve 82 may also remain completely closed when the firstvalve 80 is open to the fluid supply 84. If the second valve 82 remainsclosed, fluid will not flow as easily or at all from the air/watercylinder 32 through umbilical air channel 20 a and umbilical waterchannel 16 a.

In an alternative connection to an endoscope, as shown in FIG. 7, whenthe device is in the first position 206 causing a first fluid flow path210, the first valve 80 is open to the fluid supply 84 allowing fluid toflow downstream through the air/water supply port 42 and air supply port44 and downstream into both the umbilical water channel 16 a and theumbilical air channel 20 a meeting at the air/water cylinder 32. In thisdescription of the flow, flow through the CO₂ channel 22 is not includedbecause the CO₂ valve 36 may be closed or there may not be a CO₂channel. The fluid splits and flows three ways; a) downstream throughcontrol air channel 20 b, b) downstream through the insertion waterchannel 16 c, and c) through the air/water cylinder 32 to the secondvalve 82. The flow through the control air channel 20 b flows downstreamthrough the insertion air channel 20 c, through the air/water channel 56and exits the endoscope 12 to a drain 114 at about atmospheric pressure.The flow through the insertion water channel 16 c flows downstreamthrough the air/water channel 56 and through the air/water nozzle 46 andexits the endoscope 12 to a drain 114 at about atmospheric pressure. Theflow through the air/water cylinder 32 flows through the second valve 82and to drain line 88.

In the alternative connection to an endoscope, as shown in FIG. 8, whenthe device is in the second position 208 causing a second fluid flowpath 212, the second valve 82 is open to the fluid supply 84 allowingfluid to flow downstream through the air/water cylinder 32. In thisdescription of the flow, flow through the CO₂ channel 22 is not includedbecause the CO₂ valve 36 may be closed or there may not be a CO₂channel. The fluid splits and flows four ways; a) downstream throughcontrol air channel 20 b, b) downstream through the insertion waterchannel 16 c, and c) upstream into the umbilical water channel 16 a, andd) upstream into the umbilical air channel 20 a. The flow through thecontrol air channel 20 b flows downstream through the insertion airchannel 20 c, through the air/water channel 56 and exits the endoscope12 to a drain 114 at about atmospheric pressure. The flow through theinsertion water channel 16 c flows downstream through the air/waterchannel 56 and through the air/water nozzle 46 and exits the endoscope12 to a drain 114 at about atmospheric pressure. The flow upstream intothe umbilical water channel 16 a flows out the air/water supply port 42through the first valve 80 and to drain line 88. The flow upstream intothe umbilical air channel 20 a flows out the air/water supply port 42and the air supply port 44 through the first valve 80 and to drain line88.

The suction channel 18 may also be cleaned or sterilized by using theabove device 10. The suction channel 18 may be cleaned simultaneously byproviding third and fourth valves 90,92 or separately by connecting tothe first and second valves 80,82. The device 10 may have a third and afourth position 140, 142, with the third and fourth positionrespectively the same as the first and second positions except that thethird valve 90 replaces the first valve 80 and the fourth valve 92replaces the second valve 82. The third valve 90 may be connected to thesuction supply port 38 and the fourth valve 92 to the biopsy port 50 oralternatively to the suction control valve 34.

With the device in the third position 140 causing a third fluid flowpath 136, fluid flows downstream through the suction supply port 38,downstream through the umbilical suction channel 18 a, downstreamthrough the suction cylinder 34, downstream through the control suctionchannel 18 b, splitting into a upstream flow through the biopsy port 50and through the fourth valve 92 to the drain line 88, and a downstreamflow through the insertion suction channel 18 c and exiting the suctionopening 48 of the endoscope 12 to a drain 114 at about atmosphericpressure.

With the device in the fourth position 142 causing a fourth fluid flowpath 138, fluid flows downstream through the biopsy port 50, splittinginto a downstream flow through the insertion suction channel 18 c andexiting through the suction opening 48, and splitting into an upstreamflow through the control suction channel 18 b, upstream through thesuction cylinder 34, upstream through the umbilical suction channel 18a, upstream through the suction supply port 38 through the third valve90 and to the drain line 88.

CLEANING AND STERILIZING METHODS

The apparatus and method in accordance with the present inventionprovides both a method of sterilization of tubular structures, inparticular long, narrow, tubular structures, and a method of cleaningthe lumens of a medical device.

The sterilization method broadly includes the sterilization of theinterior of a tubular structure comprising: a) providing a tubularstructure 94, 96, b) providing a sterilizing fluid 116 c) causing thesterilizing fluid 116 to flow at a positive pressure through the tubularstructure 94, 96 in a first fluid flow path 110, and d) causing thesterilizing fluid 116 to reverse flow at a positive pressure through thetubular structure 94, 96 in a second fluid flow path 112, so that atleast part of the second fluid flow path 112 is opposite as the firstfluid flow path 110.

The sterilization method may also include providing the sterilizingfluid 116 at a temperature preferably from about 20 degrees C. to about50 degrees C. and most preferably about 40 degrees C. to about 50degrees C. The sterilizing fluid is preferably provided from about 1minute to about 20 minutes and most preferably for about 10 minutes.

The sterilizing method may also provide that the sterilizing fluid 116provided in the flow and reverse flow method of the present inventionhas a flow volume from preferably about 100 ml/min to about 1400 ml/min.The flow volume is preferably about 100 ml/min to about 250 ml/min forlumens with a diameter of about 1 mm to about 2 mm and about 600 ml/minto about 1400 ml/min for lumens with a diameter of about 3 mm to about 6mm. The sterilizing fluid 116 provided in the flow and reverse flowmethod of the present invention has a flow velocity from preferablyabout 50 cm/sec to about 500 cm/sec and most preferably about 50 cm/secto about 250 cm/sec. The sterilizing fluid 116 provided in the flow andreverse flow has a pressure preferably below about 20 psi and mostpreferably about 10 psi to about 20 psi.

The sterilization method may also include wherein the tubular structure94, 96 has a diameter of less than about 6 mm.

The sterilization method may also include starting the first fluid flowpath 110 and the second fluid flow path 112 in one end of a medicaldevice.

The sterilization method may also include starting one fluid flow path210, 212 in the control head or other central attachment point of amedical device.

The sterilization method may also include providing the device 10 of thepresent invention.

The sterilization method may also include controlling the flow and saidreverse flow by a central processor.

The present invention also includes a method of cleaning a medicaldevice with lumens 14. The cleaning method broadly includes a method ofcleaning the lumens 14 of a medical device including a) providing amedical device with a first lumen 120 and a second lumen 122, each lumen120, 122 having a proximal end 124, 128 and a distal end 126, 130 andthe distal end 126, 130 of at least one of the lumens 120,122 is open toa drain 114 at about atmospheric pressure; b) providing a cleaning fluid86; c) causing the cleaning fluid 86 to flow through the lumens 120,122in a first fluid flow path 110 starting at the proximal end 124 of thefirst lumen 120; and d) causing the cleaning fluid 86 to reverse flowthrough the lumens 120, 122 in a second fluid flow path 112 starting atthe proximal end 128 of the second lumen 122, wherein at least part ofthe second fluid flow path 112 is opposite the first fluid flow path110.

The cleaning method may also include providing a medical device with theproximal end 124, 128 of each lumen 120, 122 located in one end of themedical device.

The cleaning method may also include starting one fluid flow path 210,212 in the control head or other central attachment point of a medicaldevice.

The cleaning method may also include providing the device 10 of thepresent invention.

The cleaning method may also include draining the first fluid flow path110 through the proximal end 128 of the second lumen 122 and drainingthe second fluid flow path 112 through the proximal end 124 of the firstlumen 120.

The cleaning method may also provide that the cleaning fluid 86 providedin the flow and reverse flow has a flow volume from preferably about 100ml/min to about 1400 ml/min. The flow volume is preferably about 100ml/min to about 250 m/min for lumens with a diameter of about 1 mm toabout 2 mm and about 600 ml/min to about 1400 m/min for lumens with adiameter of about 3 mm to about 6 mm. The cleaning fluid 86 provided inthe flow and reverse flow has a flow velocity from preferably about 50cm/sec to about 500 cm/sec and most preferably from about 50 cm/sec toabout 250 cm/sec. The cleaning fluid 86 provided in the flowing andreverse flowing has a pressure preferably below about 20 psi and mostpreferably from about 10 psi to about 20 psi.

The cleaning method may also include providing the device 10 of thepresent invention.

The cleaning method may also provide controlling the flow and thereverse flow by a central processor.

The present device and method also improves sterilization of endoscopes.As shown in the following examples, complete sterilization of the lumensof endoscopes can be difficult, in particular, the CO₂ lumen of theendoscope. The CO₂ lumen typically has bends, connections, restrictions,and irregularities making it difficult to provide complete cleaning orsterilization of the CO₂ lumen.

The following tests show that the device and method of the presentinvention provides an unexpected improvement in the sterilization of theendoscope.

For the following experiments, the endoscope was coiled loosely andattached to a rack, which held it vertically. The control head wasmounted so that the eyepiece was up and the control knobs were vertical.The suction, air/water, and CO₂ channels were inoculated with a total of1-8×10⁶ spores and dried for an hour. The endoscope was treated with aperformic acid based sterilant in a device that pumped sterilant throughthe channels and sprayed the exterior of the endoscope with sterilant.The endoscope was rinsed briefly and assayed for surviving organisms. Ifeven one survivor was found, the endoscope was judged nonsterile. Asshown in the table below, a large number of variables were tested in ourefforts to sterilize endoscopes consistently. The best results seemed tobe obtained when the pressure (flow rate) in the lumens was increased to20 psi, close to the maximum allowed. We noted that survivors wererarely found in the suction channel, the largest, least complex channel.Survivors were frequently found in the CO₂ channel, which has a smalllumen and an intricate, constricted valve construction. Flowingsterilant in both directions unexpectantly consistently eliminated allof the survivors in the endoscopes including in the CO₂ channel. Asshown in the table, this procedure gave consistent sterilization evenwith a reduced pressure of 12 psi in the lumens.

TABLE I Sterilizing endoscopes with performic acid based sterilant, 10minutes at 40-45° C. Number scopes Connection sterile/total pointVariable tested Control head 4 psi pressure in lumens 0/3 10 psipressure in lumens 1/2 20 psi pressure in lumens 3/4 Light guide 4 psipressure in lumens 0/3 10 psi pressure in lumens 0/5 20 psi pressure inlumens 5/8 Control head Scope orientation -- lay 2/4 or light guide flatControl head Scope orientation -- control 0/2 knobs horizontal Scopeorientation -- control 0/2 head upside down Light guide Increasesterilant volume 1/3 three-fold Prewarm scope to 45° C. 1/2 Control headUse restrictors to channel 2/7 more flow to CO₂ channel Light guideConnect to air/water only, 2/8 flow to CO₂ channel from control headControl head Interrupt sterilant flow 1/5 or light guide with periodicair pulses Light guide Reverse flow in the CO₂ 10/10 channel

TABLE II DETAILED DATA TABLE: Improved Application of Liquids to Lumensby Reverse Flow Sterilization of endoscopes on an automatic endoscopereprocessor, 40-45° C., 15% performic acid based sterilant in RO water,10-minute exposure. Number of survivors^(k) A/W Chann A/W CO₂ Suct portConn^(f) press Other Suct^(a) CO₂ ^(b) ACI^(j) Ext port valve Port LG CHConnectors 0 0 0 0 0 0 0 0 attached 1 0 0 0 0 0 0 0 before inoculation,foamy, airpulse during sterilization (performic acid based sterilantwithout phosphoric) CH Foamy, no 0 0 1 0 0 0 0 0 airpulse LG Leakingplugs 32 TNTC TNTC 0 0 7 0 0 (modified ACI) at CH, foamy, 2 66 8 0 0 0 00 performic acid 0 0 0 0 0 0 0 0 based sterilant plus phosphoric acid CH10 12 L 0 0 0 0 0 0 0 0 psi sterilant, lay 0 0 0 0 0 0 0 0 scopes flatCH 4 Low foam by 0 0 1 0 0 0 0 0 psi low pump speed 0 3 2 0 0 0 0 0 (400rpm) 0 2 0 0 0 0 0 0 LG 4 Low foam 0 0 7 0 0 0 0 0 psi 0 1 0 0 0 0 0 0 012 4 0 0 0 0 0 CH 10 Standard 0 0 0 0 0 0 0 0 psi position, 0 1 1 0 0 00 0 raise channel pressure by restricting flow to spray arms (from thispoint forward) Knobs up on 1 111 0 0 0 0 0 control head 0 1 0 0 0 0 0Upside down 0 38 17 0 0 0 0 0 2 7 0 0 0 0 0 0 LG 10 0 13 9 0 0 0 0 0 psi0 2 0 0 0 0 0 0 LG 18- 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 psi 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 4 0 0 0 0 0 0 1 0 0 0 0 0 0 023 4 0 0 0 0 0 LG 18- 12 L sterilant 0 0 0 0 0 5 0 0 20 0 0 0 0 0 0 0 NDpsi 1 0 0 0 0 0 0 0 LG 18- Dry at 45° C. 2 TCTN TNTC 0 0 0 0 0 20 0 0 00 0 0 0 0 CH 18- 0 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 06 0 0 0 0 0 CH 18- Add restrictor 0 2 17 0 0 0 0 0 20 to A/W 0 0 0 0 0 00 0 connector on light guide end CH 18- As above. 0 P 41^(h) 0 0 0 0 020 Sample A/W in 24^(g) both E 9 directions 0 P 16^(l) 0 0 0 0 0 fromcontrol 6 head, sample E1 CO₂ from 7 control head to light guide as wellas entire channel CH 18- Clamp on CO₂ 0 2 6 0 0 0 0 0 20 valve to hold 00 0 0 0 0 0 0 it open, 0 0 1 0 0 0 0 0 smaller restrictor on A/Wconnector on light guide end LG 18- Connect 0 0 0 0 0 0 0 0 20 suction &0 1 0 0 0 0 0 0 A/W only, tight restrictor on prong, standard inoculumLG Connect 0 2 2 0 0 0 0 0 suction, A/W, 5 0 1 0 0 0 0 0 and CO₂, norestrictor, standard inoculum, run at 400 rpm as has been done above toreduce foam LG 9- Connect 0 0 1 0 0 0 0 0 10 suction, A/W 0 1 0 0 0 0 00 and CO₂, no 0 0 4 0 0 0 0 0 restrictor, standard inoculum, run at 800rpm, foamy LG 9- As above 0 0 0 0 0 0 0 0 10 except try to 0 2 2 0 0 0 00 inoculate distal end only of air/water/CO₂ channel (˜0.3 ml inoculumrather than 5) LG 9- As above 0 1 0 0 0 0 0 0 10 except lay A/W = scopesas flat 3^(j) as possible in 0 5 6 0 0 0 0 0 rear of bay A/W = 2 LG 13-Connect 0 0 0 0 0 0 0 0 14 suction, A/W 0 0 0 Mold 0 0 0 0 and airprong, standard 0 17 33 0 0 0 0 0 inoculum, 800 A/W = rpm 4 0 2 2 0 0 00 0 10- Connect 0 0 0 0 0 0 0 0 12 suction, A/W, restrictor on 0 28 14 00 0 0 0 prong. A/W = Inoculate 1 exterior- back of knob, insertion tube,control head 11- Purge with air 0 6 1 0 0 0 0 0 12 for 5 sec in A/W =every minute 1 of exposure, 0 4 1 0 0 0 0 0 connect as above 12- Purgewith 0 1 3 0 0 0 0 0 13 air for 15 sec every other minute of exposure(total of 4 times), connect as above 10- Alternate 0 0 0 0 0 0 0 0 13direction 0 0 0 0 0 0 0 0 of flow in 0 0 0 0 0 0 0 0 CO₂ channel 0 0 0 00 0 0 0 every 0 0 0 0 0 0 0 0 minute of 0 0 0 0 0 0 0 0 exposure, 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 No 0 0 0 0 0 0 0 0 preheat,otherwise as above ^(a)Suction channel flushed and brushed first ^(b)CO₂channel flushed with syringe then all channels flushed with all-channelirrigator for ACI count ^(c)The tubing connection to the air/water andCO₂ channels was disconnected when the scope was partially removed fromthe chamber. It is possible that it came loose during the cycle. ^(d)Theexposure cycle was stopped for about 1 minute. The light guide end felloff the rack and pulled a tubing connection loose. ^(e)Filters cloggedduring survivor recovery from neutralizer, most probably due to agarpresent in the neutralizer from previous use of bottle ^(f)LG = lightguide, CH = control head ^(g)P = control head to light guide, E = entirelength of channel ^(h)A/W only -- proximal (CH to LG) = 0, distal end(CH to nozzle) = 3 ^(I)A/W proximal = 0, distal end = 0 ^(j)After (andincluding) 46^(th) test sampled the air and water channels from thelight guide end to distal tip. This was done after the gas channelsampling but before the ACI. Results are reported only if there weresurvivors. ^(k)If the number of survivors is >0, the test failed.

Although the description of the preferred embodiment has been presented,it is contemplated that various changes, including those mentionedabove, could be made without deviating from the spirit of the presentinvention. It is therefore desired that the present embodiment beconsidered in all respects as illustrative, not restrictive, and thatreference be made to the appended claims rather than to the foregoingdescription to indicate the scope of the invention.

We claim:
 1. A method of cleaning the lumens of a medical devicecomprising: a) providing a medical device with a first lumen and asecond lumen, said first and second lumens each having a proximal endand a distal end, and said distal end of at least one of said lumensopen to a drain at about atmospheric pressure; b) providing a cleaningfluid; c) causing said cleaning fluid to flow at a positive pressurethrough said first and second lumens in a first fluid flow path, saidfirst fluid flow path starting at said proximal end of said first lumen;and d) causing said cleaning fluid to reverse flow at a positivepressure through said first and second lumens in a second fluid flowpath, said second fluid flow path starting at said proximal end of saidsecond lumen, wherein at least part of said second fluid flow path isopposite said first fluid flow path.
 2. The method of claim 1 whereinsaid proximal end of said first lumen and said proximal end of saidsecond lumen are located in one end of said medical device.
 3. Themethod of claim 1 wherein one of said fluid flow paths starts in acontrol head of said medical device.
 4. The method of claim 1 whereinsaid first fluid flow path drains through said proximal end of saidsecond lumen and said second fluid flow path drains through saidproximal end of said first lumen.
 5. The method of claim 1 wherein flowand reverse flow volumes are from about 100 ml/min to about 1400 ml/minat a pressure below about 20 psi.
 6. The method of claim 1 wherein flowand reverse flow are from about 50 cm/sec to about 500 cm/sec.
 7. Themethod of claim 1 wherein said first fluid flow path is downstreamexcept for upstream through a control air channel, upstream through anair/water cylinder, upstream through an umbilical air channel, upstreamthrough an air/water supply port, upstream through said second valve,and upstream through an umbilical water channel; and said second fluidflow path is downstream except for upstream through a control CO₂channel, upstream through a CO₂ cylinder, upstream through an umbilicalCO₂ channel, upstream through a CO₂ supply port, and upstream through afirst valve.
 8. The method of claim 1 wherein said flow and said reverseflow are controlled by a central processor.
 9. The method of claim 1wherein said lumen is long and narrow.
 10. The method of claim 1 whereinsaid first lumen or said second lumen has a length and a diameter, saidlength from about 200 to about 8000 times said diameter.
 11. The methodof claim 1 wherein said cleaning fluid is a liquid.